Reciprocating lifting mechanism for the gripper-rail in an automatic spool change installation of spinning, twisting and the like type machines

ABSTRACT

An improved reciprocating lifting mechanism for raising and lowering a gripper-rail within an automatic spool changing installation for spinning, twisting and the like type machines which includes at least two substantially identical, equal-sided rectilinear guidance linkage systems, a driving mechanism for moving the gripper-rail through the linkage systems, and structure for the automatic predetermined variation of the regulating velocity of the driving mechanism during the lifting strokes of the gripper-rail.

United States Patent 1 91 1111 3,823,538 Ige ,iuly 16, 1974 [54] RECIPROCATING LIFTING MECHANISM 3,398,519 8/1968 Haussmann 57/54 X FOR THE GRIPPERPRAIL IN AN 3,403,494 10/1968 Livingston 57/52 X 3,550,368 12/1970 Marenco 57/52 AUTOMATIC SPOOL CHANGE 3,566,598 3/1971 Godfrey..... 57/54 INSTIkLLA'IXOII 0F SPINNING, TWESTING 3,686,847 8/1972 Vignon 57/52 AND THE LIKE TYPE MACHINES Wolfgang lgel, Ebersbach, Germany Zinser-Texilmaschinen GmbH, Ebersbach, Germany Filed: Apr. 17, 1973 Appl. No.: 351,976

Inventor:

Assignee:

Foreign Application Priority Data Apr. 17, 1972 Germany 22185804 U.S. Cl. 57/52 Int. Cl, 1001b 9/04 Field of Search 57/34 R, 52, 53, 54, l R

References Cited UNITED STATES PATENTS 12/1967 Shoji et al. 57/52 UX Primary Examiner-Donald E. Watkins Attorney, Agent, or Firm-Edwin E. Greigg [5 7] ABSTRACT An improved reciprocating lifting mechanism-for rais-- ing and lowering a gripper-rail within an automatic spool changing installation for spinning, twisting and 13 Claims, 5 Drawing Figures RECIPROCATING LIFTING MECHANISM FOR THE GRlPPER-RAIL IN AN AUTOMATIC "I 1 CHANGE INSTALLATION OF SPINNING, TWISTING AND THE LIKE TYPE MACHINES BACKGROUND OF THE INVENTION The present invention relates to a reciprocating lifting mechanism for raising and lowering a gripper-rail comprising at least one gripper for the gripping of full or empty spools in an automatic spool changing installation for spinning, twisting and the like type machines. More particularly, the present invention relates to an improved reciprocating lifting mechanism for a longitudinally extending gripper-rail which is rectilinearly movable perpendicular to its longitudinal direction and guided in its rectilinear movement by at least two substantially identical, equal-sided rectilinear guidance linkage systems whose motions are coupled with one another and which are disposed at a linearly adjacent distance from one another, the gripper rail being raised and lowered through the rectilinear guidance linkage systems by at least one driving mechanism, with each rectilinear guidance linkage system having a lower joint movable in a horizontal direction, and with at least one of the lower joints being moved by the driving mechanism.

In known devices of this type, the lower joint of at least one of the rectilinear guidance linkage systems is pivotably mounted to a sled member guided rectilinearly on a horizontal guide rail. The sled is reciprocated back-and-forth in the horizontal direction by a hydraulic piston-cylinder unit in order to effect the raising and lowering of the gripper-rail. This has the disadvantage, however, that the speed of adjustment of the regulating velocity imparted by the piston-cylinder unit to the gripper-rail is not transformed in a constant ratio into the reciprocating velocity of the gripper-rail. Rather the reciprocating velocity of the gripper-rail in the upward direction diminishes rapidly with a constant regulating velocity of the piston cylinder unit, while in the downward direction of the gripper-rail its velocity is at first very low and thereafter increases only slowly. This results in a considerable slowing of the spool changing process, and can also lead to difficulties insofar as sensitive control of the velocities of motion of the gripperrail is concerned.

OBJECTS, SUMMARY AND ADVANTAGES OF THE INVENTION It is, therefore, a general object of the present invention to overcome the above noted disadvantages of the known art.

It is a more specific object of the present invention to provide an improved reciprocating lifting mechanism which includes structure for the automatic predetermined variation of the regulating velocity imparted to the gripper-rail within an automatic spool changing installation for spinning, twisting and the like type machine.

These and other objects are accomplished according to the present invention by the provision in a reciprocating lifting mechanism of means for the automatic predetermined variation of the-regulating velocity of the driving mechanism during the lifting strokes of the gripper-rail which are in turn effected as a result of the horizontal movements of at least one of the movable lower joints of the substantially identical rectilinear guidance linkage systems.

In the reciprocating lifting mechanism according to the present invention, the regulating velocity of the driving mechanism and therefore the velocity of the horizontally movable joint can be varied in whatever way is appropriate during the reciprocating lifting motion of the gripper-rail so that a desired development of the velocity of the reciprocating lifting of the gripperrail will result. The advantages of the rectilinear guidance linkage systems are fully retained. These advantages consist especially in a precise, stable, and freely moving rectilinear guidance of the gripper-rail. The velocity development of the reciprocating lifting motion of the gripper-rail can be suitably chosen in many cases so that the gripper-rail performs its upward and downward stroke with approximately uniform velocity.

In a preferred embodiment, it is provided that the velocity of the gripper-rail is smaller in a region adjacent to the reversal point or the lower limit of travel of the gripper-rail stroke, than it is in the middle of its stroke because in this lower partial region, the grippers arrive at the gripping position where they grip the empty spools or where they deposit the full spools borne by them on a conveyor belt or the like. In the vicinity of the upper reversal point or the upper limit of travel of the gripper-rail stroke, a velocity reduction of the reciprocating lifting motion can be provided as well, so that the motion of the gripper-rail occurring there, or the entry of the grippers into the spools located on the spindles and the removal and replacement of spools from or onto the spindles does not occur too fast. A particularly advantageous development of the velocity of the reciprocating lifting motion of the gripper-rail can be chosen so that the lifting velocity of the gripperrail, beginning at or in the vicinity of at least one reversal point of the lifting motions, increases continuously with approximately uniform acceleration up to approximately the middle of the corresponding stroke and then decreases again continuously. In this way, the lifting movements of the gripper-rail can be executed particularly fast and with relatively low values of acceleration and deceleration. Moreover, this can be achieved with weaker driving motors and weaker transmission links and joints, because of the lower decelerations and accelerations achieved than would be the case if one worked with rapid variations of velocity in the vicinity of the reversal point.

The regulating speed of the driving mechanism can be controlled with any suitable devices. It can also be automatically controlled, preferably in dependence on the position of the rectilinear guidance linkage systems.

The latter has the advantage that the regulating speed of the driving mechanism is always coupled to the position of the rectilinear guidance linkage systems so that a predetermined time variation of velocity of the lifting motions is particularly precisely effected with unintentional variations of the regulating velocity of the driving mechanism not adding together during the lifting motion.

In some cases it can be suitably provided that the regulating velocity of the driving mechanism be controlled or regulated by a time-dependent program. This has the advantage that the time-dependent program may be stored in program carriers of any type, for example, on cards, and that by simple exchange of such program carriers, different velocity developments of the lifting motion of the gripper-rail can be selected. However, such program carriers, for example, program control cards, can be provided even if a time-dependent program is not used, if the regulating velocity of the driving mechanism is changed in dependence on the position of the rectilinear guidance linkage systems, by coupling the advance of the program carrier with the motion of a moving part of the rectilinear guidance linkage systerns, or of the gripper-rail or of the driving mechanism.

In most cases it is sufficient if the manufacturer of the lifting mechanism or of the corresponding spinning, twisting or the like type machine provides a single program according to which the regulating velocity of the driving mechanism is altered. Especially in that case it can be provided advantageously that the regulating velocity of the driving mechanism is controllable by a mechanical control cam whose motion is directed by at least one of the rectilinear guidance linkage systems. It can also be suitable in may cases to move the control cam directly by means of the driving mechanism and, preferably, to dispose it at one of the movable links of the driving mechanism. In a hydraulic piston-cylinder unit, this can suitably be the piston rod.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a schematic illustration of a reciprocating lifting mechanism according to the present invention within the automatic spool changing mechanism not shown in further detail for a spinning, twisting and the like type machine, not shown. The lifting mechanism includes a driving'mechanism and one exemplary embodiment of a control mechanism according to the present invention for influencing the regulating velocity of the driving mechanism.

FIG. 2 schematically illustrates an exemplary alternative embodiment of the control mechanism according to the present invention for influencing the regulating velocity of the driving mechanism.

FIG. 3 schematically illustrates a further exemplary alternative embodiment of the control mechanism of FIG. 2.

FIG. 4 is a schematic illustration of still another exemplary embodiment of the present invention according to which a change in the output velocity of the driving mechanism is effected by means of an infinitely variable transmission.

FIG. 5 is a schematic illustration of yet another exemplary embodiment of the present invention according to which a change in the output velocity of the driving mechanism is effected by means of a controlled electric motor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to a more specific consideration of the exemplary embodiments according to which like parts are represented by like numerals, FIG. 1 illustrates only the important components within an automatic spool changing mechanism of a spinning, twisting or the like type machine necessary for an understanding of the present invention. For the sake of clarity, further details of the machine are not shown. The illustrated installation includes a gripper-rail 11 which is movable up-and-down in a reciprocating fashion in the direction of the double arrow A by means of a driving mechanism which is preferably a hydraulic piston-cylinder unit 50, through the intermediary action of two substantially identical, equal-sided rectilinear guidance linkage systems 17 and 18. Further details of the automatic spool changing installation are also not shown for clarity. It should be understood that the driving mechanism can be pneumatic piston cylinder unit or the like. The piston-cylinder unit includes a horizontal guide rod 24 which serves as a piston rod for the unit 50 and as a mounting rod for a portion of each rectilinear guidance linkage system 17 and 18. g

In addition to the rectilinear displacement of the gripper-rail 11, in the direction of the double arrow A, it is also pivotable between limits about the geometric longitudinal axis of the horizontal guide rod 24 in unison with the two rectilinear guidance linkage systems 17 and 18 by means of a motorized pivoting device (not shown).

The guide rod 24 is rectilinearly guided through bearings 7. The bearings 7 are in turn mounted within stationary bearings 7 to be rotatable but not axially slidable. The guide rod 24 is fixedly connected with the piston 52 of the piston-cylinder unit 50 so that it is movable back-and-forth or reciprocated in the horizontal direction in indicated by the double arrow C. On guide rod 24, two bearing blocks 24 are fixedly mounted. To these bearing blocks are pivotably mounted by means of joints 23 the long rods 20 of rectilinear guidance linkage systems 17 and 18. The upper ends of the long rods 20 are in turn pivotably mounted at 21 to the gripper-rail l l. The linkage systems 17 and 18 further comprise short rods 19 whose lower ends are pivotably mounted at 29 to a respective bearing 7 and whose upper ends are pivotably mounted at 30 to a respective rod 20. The mounting at 30 is located approximately at the midpoint of the respective rod 20.- It should be noted that all the pivotable mountings are of a conventional nature. The joints 23 are movable horizontally back-and-forth by means of the driving mechanism 50, and in consequence of the axial motion of the guide rod 24. In this way, a vertical lifting movement of the gripper-rail 11 is effected.

In order that the lifting velocity of the gripper-rail l 1 not be determined by the kinematics of the rectilinear guidance linkage systems 17 and 18, but rather that the development of this velocity be such that the lifting strokes require the least amount of time, the regulating velocity of the piston-cylinder unit 50 is controlled by control means including an adjustable volumetric valve 55. The valve 55 is preferably interposed in the hydraulic feed line of the piston-cylinder unit 50. Preferably, the volumetric valve 55 is a throttle valve, whose throttling action is controlled in dependence on the position of the gripper-rail 11 by means of a chain drive 56. The chain drive 56 comprises two rotatably mounted chain sprockets 57, which are mounted to be stationary rela tive to the machine, and an endless chain 58. The chain 58 is connected with the gripper-rail 11 at 53 so that a control rod 59, which is driven by the lower chain sprocket 57 via a sector drive which is not shown, is positively coupled to the gripper-rail 11. According to this exemplary embodiment, the throttle valve 55 can be suitably constructed so that it varies the regulating velocity of the piston-cylinder unit 50 in dependence on the position of the gripper-rail 11, and therefore in dependence on the position of the linkage systems 17 and 18. Accordingly, there results an approximate compensation for the change in the transmission ratio of the rectilinear guidance linkage systems 17 and 18 which occurs in dependence on the position of the gripper-rail 11, with the effect that the gripper-rail 11 is driven in both lifting directions, that is, away from and toward the guide rail 24, with approximately a constant lifting velocity.

Also inserted in the hydraulic circuit of the pistoncylinder unit 50 is a 4/2-way valve 49 which, in the position shown, has the effect that piston 52 is moved to the right (FIG. 1). In its other position, the valve 49 causes the piston 52 to move toward the left. The hydraulic circuit is completed by a reservoir 62 from which hydraulic fluid is pumped by a pump 60 and to which the hydraulic fluid is delivered from the pistoncylinder unit 50. The pump 60 is driven by a motor 61.

Turning now to FIG. 2 an alternate embodiment of the control means for the control of the volumetric valve 55 is shown. Except for the changed structure shown, the other parts of the control means correspond to that of the embodiment of FIG. 1. According to this alternate embodiment the adjustable volumetric valve 55 has a rotatably mounted positioning arm 59 which regulates, depending on its relative position, the throughput volume of the fluid from the hydraulic circuit and therefore the velocity of the guide rod 24. The positioning arm 59' always abuts the control edge 63 of a mechanical cam-piece 64, which is positively connected wit the gripper-rail 11. In this way the control edge 63 controls the velocity of the hydraulic pistoncylinder unit 50 (not shown in this illustration), and therefore the velocity of the guide rod 24 in dependence on the position of the gripper-rail 11.

In the further exemplary embodiment illustrated in FIG. 3, the adjustable volumetric valve 55 is controlled by means of a cam plate 66 which is positively connected with a shaft 65 of the lower joint 29 of one of the short rods 19. The shaft 65 is mounted to the bearing 7. The cam plate has a spiral-shaped control edge 63' which is fashioned in such a way that a desired development of the velocity of the lifting strokes of the gripper-rail ll is achieved.

In the still further exemplary embodiment illustrated in FIG. 4, one end of the guide rod 24 is developed as a rack-rod 76, and is further supported in a bearing 77 at some distance from one of the bearings 7. An electric motor 78, which can have several constant drive speeds, and which can run in the clockwise as well as the counterclockwise directions through an infinitely variable transmission 79, drives a pinion 90 which meshes with the rack-rod 76. The step-down ratio of the transmission 79 is adjustable by means of a lever 91 which is pivotable in dependence on the position of the gripper-rail 11 via a connecting rod 92. For this purpose the connecting rod 92 is in turn pivotably mounted to the gripper-rail 11. With this embodiment the transmission ratio to the gripper-rail 11 is changed in such a way that a desired development of the velocity of the gripper-rail 11 during its lifting movements or strokes is achieved. It is particularly suitable to have a motor 78 which has two different rotational speeds, so that it is possible to change from the higher to the lower rotational speed in the vicinity of the reversal point of the lifting stroke, that is in the vicinity of that point where the stroke changes direction.

In the still further exemplary embodiment illustrated in FIG. 5, the horizonal guide rod 24 is equipped with an external thread at the end shown, for the purpose of its axial displacement. This thread meshes with an internal thread of a rotatably mounted threaded nut 67 which is driven by an electric motor 69 through the gear set 70. The electric motor 69 is a direct current motor which can be switched for clockwise and counterclockwise rotation by means of a switch (not shown). In the field or armature current circuit of the motor 69 an adjustable ohmic resistance 71 is connected, by means of which the rotational speed of the motor 69, and therefore the velocity of advance of the guide rod 24, can be infinitely varied. The variation of this resistance 71 could, for example, in a manner not further shown, occur in principle in the same way as the variation of the volumetric valves 55, according to FIGS. 1 3, or in some other suitable way. If desired, however, a servo-control of the lifting velocity of the gripper-rail 11 can also be provided, for example, with the components shown in broken lines. The method of operation of these components will be explained more fully below.

In the exemplary embodiments described above, the variation of the regulating velocity of the driving mechanisms is achieved by means of control means and not by means of regulating or servo-control means. Since control installations are constructionally simpler than servo-control installations, and since in generalthe precision of the intended time-variation of the velocity of the lifting stroke of the gripper-rail 11 does not have to be high, such control means are usually completely sufficient. However, if in special cases the gripper-rail 11 must be moved, during at least part of its stroke, with a precisely constant velocity, and/or if its velocity must be varied exactly according to a preset program, then a regulating or servo-control of the lifting velocity of the gripper-rail 11 may be provided. In this case, the velocity of the gripper-rail 11 or of the movable parts of the rectilinear guidance linkage systems 17 and 18 must be continuously measured and compared with a constant nominal value or with a nominal value varying according to a program, and from the difference between the actual value and the nominal value, a regulating or servo-control signal must be derived, by means of which the regulating velocity of the drive mechanism is continuously influenced in such a way that the deviation between the nominal value and the actual value is continuously regulated away, that is, continuously regulated toward zero.

A simple example of a servo-control is explained with the aid of the broken-line drawing in FIG. 5. If a con stant lifting velocity of the gripper-rail 11 is desired, then the lifting velocity may be measured continiously by means, for example, of a tacho generator 95 driven, for example, by a rack-rod driver 94. The output of the tacho-generator 95 can be imposed on a controller 96 which compares it with a constant nominal value and forms a control deviation signal. The resistance 71 is in turn automatically adjusted, for example, by means of a setting motor 97 in dependence on the control signal, which is diminished in the sense described above.

What is claimed is:

1. In a reciprocating lifting mechanism for raising and lowering a longitudinally extending and rectilinearly movable gripper-rail within an automatic spool changing installation for spinning, twisting and the like type machines, the gripper-rail having at least one gripper for gripping full and empty spools of these machines,

velocity of the driving mechanism during the lifting strokes of the gripper-rail, said lifting strokes being effected by the horizontal movement of the lower joints.

2. The reciprocating lifting mechanism as defined in claim 1, wherein the regulating velocity of the driving mechanism is varied in dependence on the position of the rectilinear guidance linkage systems.

3. The reciprocating lifting mechanism as defined in claim 2, wherein said improvement means includes a mechanical control cam, and wherein the regulating velocity of the driving mechanism is varied by said mechanical control cam whose motion is in turn controlled by at least one of the rectilinear guidance linkage systems.

4. The reciprocating lifting mechanism as defined in claim 1, wherein said improvement means includes a motor means, and control means for controlling the drive speed of said motor means and wherein the regulating velocity of the driving mechanism is varied by adjustment of the drive speed of said motor means by said control means.

5. A reciprocating lifting mechanism as defined in claim 4, wherein the improvement further comprises means connecting said control means to said rectilinear guidance linkage systems, wherein said motor means includes a supply line, and wherein said control means is connected to said motor means through said supply line and is automatically variable in dependence on the position of the rectilinear guidance linkage systems.

6. A reciprocating lifting mechanism as defined in claim 5, wherein said motor means comprises a direct current electric motor and a setting member, said setting member comprising an adjustable ohmic resistance member which is connected in the armature current circuit of said electric motor, and wherein the rotational speed of said electric motor is adjustable by said ohmic resistance member.

7. A reciprocating lifting mechanism as defined in claim 5, wherein said motor means comprises a direct current electric motorand a setting member, said setting member comprising an adjustable ohmic resistance member which is connected in the field current circuit of said electric motor, and wherein the rotational speed of said electric motor is adjustable by said ohmic resistance member.

8. A reciprocating lifting mechanism as defined in claim 5, wherein said motor means comprises a hydraulic piston-cylinder unit, and a setting member, said setting member comprising an adjustable volumetric valve.

9. A reciprocating lifting mechanism as defined in claim 5, wherein said motor means comprises a pneumatic piston-cylinder unit and a setting member, said setting member comprising an adjustable volumetric valve.

10. A reciprocating lifting mechanism as defined in claim 1, wherein said improvement means includes an infinitely variable transmission means, and wherein the regulating velocity of the driving mechanism is varied by changing the transmission ratio of said transmission means.

11. A reciprocating lifting mechanism as defined in claim 1, wherein the regulating velocity of the driving mechanism is varied in dependence on the motion of the rectilinear guidance linkage systems in such a way that a substantially constant lifting velocity of the gripper-rail results.

12. A reciprocating lifting mechanism as defined in claim 1, wherein the velocity of the gripper-rail is smaller in a region adjacent to the lowest point of its stroke than in the middle of its stroke.

13. A reciprocating lifting mechanism as defined in claim 1, wherein the lifting velocity of the gripper-rail continuously increases with approximately uniform acceleration beginning in substantially the vicinity of at least one of the end points of its stroke to approximately the middle of of the corresponding stroke and thereafter decreases continuously. 

1. In a reciprocating lifting mechanism for raising and lowering a longitudinally extending and rectilinearly movable gripper-rail within an automatic spool changing installation for spinning, twisting and the like type machines, the gripper-rail having at least one gripper for gripping full and empty spools of these machines, the mechanism including: at least two substantially identical, equal-sided rectilinear guidance linkage systems whose motions are coupled and which are disposed at a linearly adjacent distance from one another, with the gripper-rail being rectilinearly moved perpendicular to its longitudinal extent by the linkage systems, and with each of the linkage systems having a lower joint movable in a horizontal direction; and a driving mechanism for moving at least one of the lower joints to thereby move the gripper-rail through the linkage systems, the improvement comprising means for the automatic predetermined variation of the regulating velocity of the driving mechanism during the lifting strokes of the gripper-rail, said lifting strokes being effected by the horizontal movement of the lower joints.
 2. The reciprocating lifting mechanism as defined in claim 1, wherein the regulating velocity of the driving mechanism is varied in dependence on the position of the rectilinear guidance linkage systems.
 3. The reciprocating lifting mechanism as defined in claim 2, wherein said improvement means includes a mechanical control cam, and wherein the regulating velocity of the driving mechanism is varied by said mechanical control cam whose motion is in turn controlled by at least one of the rectilinear guidance linkage systems.
 4. The reciprocating lifting mechanism as defined in claim 1, wherein said improvement means includes a motor means, and control means for controlling the drive speed of said motor means and wherein the regulating velocity of the driving mechanism is varied by adjustment of the drive speed of said motor means by said control means.
 5. A reciprocating lifting mechanism as defined in claim 4, wherein the improvement further comprises means connecting said control means to said rectilinear guidance linkage systems, wherein said motor means includes a supply line, and wherein said control means is connected to said motor means through said supply line and is automatically variable in dependence on the position of the rectilinear guidance linkage systems.
 6. A reciprocating lifting mechanism as defined in claim 5, wherein said motor means comprises a direct current electric motor and a setting member, said setting member comprising an adjustable ohmic resistance member which is connected in the armature current circuit of said electric motor, and wherein the rotational speed of said electric motor is adjustable by said ohmic resistance member.
 7. A reciprocating lifting mechanism as defined in claim 5, wherein said motor means comprises a direct current electric motor and a setting member, said setting member comprising an adjustable ohmic resistance member which is connected in the field current circuit of said electric motor, and wherein the rotational speed of said electric motor is adjustable by said ohmic resistance member.
 8. A reciprocating lifting mechanism as defined in claim 5, wherein said motor means comprises a hydraulic piston-cylinder unit, and a setting member, said setting member comprising an adjustable volumetric valve.
 9. A reciprocating lifting mechanism as defined in claim 5, wherein said motor means comprises a pneumatic piston-cylinder unit and a setting member, said setting member comprising an adjustable volumetric valve.
 10. A reciprocating lifting mechanism as defined in claim 1, wherein said improvement means includes an infinitely variable transmission means, and wherein the regulating velocity of the driving mechanism is varied by changing the transmission ratio of said transmission means.
 11. A reciprocating lifting mechanism as defined in claim 1, wherein the regulating velocity of the driving mechanism is varied in dependence on the motion of the rectilinear guidance linkage systems in such a way that a substantially constant lifting velocity of the gripper-rail results.
 12. A reciprocating lifting mechanism as defined in claim 1, wherein the velocity of the gripper-rail is smaller in a region adjacent to the lowest point of its stroke than in the middle of its stroke.
 13. A reciprocating lifting mechanism as defined in claim 1, wherein the lifting velocity of the gripper-rail continuously increases with approximately uniform acceleration beginning in substantially the vicinity of at least one of the end points of its stroke to approximately the middle of of the corresponding stroke and thereafter decreases continuously. 